Description
2004 GMC Sierra 6.6L ECM / ECU – VIN Programmed | Updated
This Engine Control Module (ECM / ECU) is a genuine OEM replacement for all 2004 GMC Sierra 6.6L models.
Each unit is VIN-programmed, updated, and fully tested for a true plug-and-play installation with our cloning service.
Built to OEM standards for reliability, calibration accuracy, and long-term performance.
Strict Testing & Quality Assurance
Every ECU is inspected, refreshed, and verified through advanced diagnostic tools. Testing includes:
Complete communication & CAN-bus verification
Sensor input/output and signal integrity checks
Injector & ignition pulse simulation
Power, ground, and load-circuit analysis
Flash memory integrity and checksum validation
Thermal and voltage-stress testing to confirm reliability
Important Note
Some vehicles with IMMO or PATS require key programming after installation. This is normal.
For a 100% plug-and-play solution, we recommend using our full cloning service. We transfer all security data to the replacement unit.
A prepaid shipping label will be emailed to you. Allow you to mail in your original computer to us for full cloning.
If cloning is not selected, the ECU will be VIN programmed, and a key relearn will be required after installation.
Contact Us
Email: info@fixecm.com
Phone: Local: 647-247-8555 | Toll-Free: 1-800-915-5566
Frank James –
Received my 2004 GMC Sierra ECM quickly with free shipping, and it was perfectly programmed for my VIN—smooth plug-and-play installation.
They answered all my questions right away and had my ECM reprogrammed fast, making the whole process hassle-free.
Great service with professional ECU programming and very reasonable shipping costs; my truck runs like new again!
Super fast turnaround and excellent communication throughout—my PCM arrived VIN programmed and ready to go.
The updated ECM fit perfectly and was shipped quickly without any extra cost, highly recommend!
Luke Taylor –
I ordered the 2004 GMC Sierra 6.6L ECM and was really impressed with how smoothly everything went. The unit arrived quickly with free shipping, which was a huge plus. The programming was spot on, and the truck fired up without any issues right away. I also appreciated the team’s quick responses when I had a couple of questions before ordering.
David Ramirez –
I was a bit nervous about ordering an ECM online, but this 2004 GMC Sierra 6.6L unit arrived quickly and was already VIN programmed, which saved me a ton of hassle. The team was really helpful, answering all my questions promptly and keeping me updated throughout the process. Installation was straightforward, and the truck fired up right away with no issues. Shipping was free and surprisingly fast, making the whole experience smooth from start to finish. Definitely recommend this if you need a reliable replacement without the usual headaches.
Luke Murphy –
I recently purchased the 15231599 ECM for my 2004 GMC Sierra 6.6L, and I couldn’t be happier with the experience. The unit arrived quickly, and I was impressed that they included free shipping—definitely a nice bonus. What really stood out was the plug-and-play programming service they provided, which made installation hassle-free. I had a few questions during the process, and their support team responded promptly, making the whole process smooth. The truck runs like new again, and I highly recommend this product to anyone looking for a reliable ECM replacement.